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Vivian M Sueiras, Vincent Moy, Noel Marysa Ziebarth; Age-Dependency of Diffusion within the Human Lens Capsule. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5735.
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© ARVO (1962-2015); The Authors (2016-present)
To determine if diffusion within the human lens capsule changes as a function of age.
Whole lenses from 7 human cadavers (age: 21-61 years) were retrieved from the Florida Lions Eye Bank. When the technicians harvested donor corneas suitable for transplantation, they also removed the lenses for use for this project. The human lenses arrived from the eye bank in sealed vials filled with Dulbecco’s modified eagle medium placed in Styrofoam containers filled with ice. The whole lenses were stored in the refrigerator at 4°C before they were used. The anterior lens capsule was separated from the lens using the continuous curvilinear capsulorhexis technique. Each excised capsule was submerged in a 0.01% solution of anionic, fluorescein-labeled dextran in PBS (500kD MW). The samples were soaked overnight, allowing the molecules to diffuse into the capsule and to reach chemical and diffusional equilibrium. The capsules were then removed from the bath, washed 2 times with PBS, plated on a glass bottom dish, and hydrated with PBS. Fluorescence recovery after photobleaching (FRAP) experiments using a Nikon A1R confocal microscope were conducted on the lens capsules to quantify diffusion. The argon laser was used to bleach out a circle of radius 10μm at a plane within the capsule, creating a region of interest (ROI). Changes in fluorescence intensity stemming from the diffusion of the fluorescent tracer were monitored over time for 120 seconds. This data was normalized using an “unbleached” region away from the ROI. The time to half recovery was determined for each sample.
The time to half maximum recovery ranged from 6.24 to 7.85s. Prior to 40 years of age, the half maximum recovery time was constant and averaged 6.29 ± 0.06s. After 40 years of age, the recovery time linearly increased, indicating that transport was impeded in older lenses.
With age, the rate of transport of dextran within the lens capsule significantly slows. These results could indicate that the diffusion of molecules relevant to lens biology is also impeded in older lens capsules.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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